9 Things You Probably Didn't Know About Your Body's Internal Clock

Sure, you can adjust the time displayed on your alarm clock for the Daylight Saving Time change, but your body might not be so quick to take a hint. And you can thank your internal clock for that.

Internal clocks, technically called circadian rhythms, are actually a series of internal variations in the body controlled by the brain that occur along a roughly 24-hour cycle. They are highly sensitive to light, and the lack thereof associated with Sunday's end of Daylight Saving Time can throw off your internal clocks for days.

Scientists still don't have all the answers when it comes to circadian rhythms, but what is known is pretty interesting. Here are a few fun facts you may not have heard before.

Electronic light is totally screwing up your internal clock. Darkness is our biggest natural clue that bedtime is approaching. Artificial light, whether it comes from a lamp, the TV or even just your smartphone, can trick the brain into thinking it’s time to stay awake and alert rather than settle down. "Technology has effectively decoupled us from the natural 24-hour day to which our bodies evolved, driving us to go to bed later," Charles A. Czeisler, M.D., Ph.D., a professor of sleep medicine at Harvard Medical School, wrote in 2013. "And we use caffeine in the morning to rise as early as we ever did, putting the squeeze on sleep."

Camping could help reset it to a more natural rhythm. Luckily, eliminating technology from the bedroom can be a quick fix, but those of us who are hyper-connected may find that to be easier said than done.

When there’s no possible way to stay plugged in, your body might have an easier time syncing up to a more natural cycle. In a small study from the University of Colorado at Boulder, a week-long camping trip seemed to reset campers’ circadian rhythms closer to sunrise and sunset. "What we found is that natural light-dark cycles provide a strong signal that reduces the differences that we see among people -- night owls and early birds -- dramatically,” study researcher Kenneth Wright said in a statement.

You can give yourself jet lag without buying a plane ticket. You don’t have to travel across three time zones to trick your brain into thinking you have. In fact, staying up later than usual and then sleeping in, say on a Saturday and Sunday, can leave you groggy and irritable when it’s time to get back to your normal routine come Monday morning. This phenomenon even has a name: social jet lag. Straying from your normal sleep and wake routine like this confuses your internal clock, leading to difficulty falling asleep Sunday night -- and, consequently, a rough Monday morning. To avoid social jet lag altogether, experts recommend going to sleep each night and waking up each morning as close to the same time as possible (yes, even on weekends). If that simply isn’t going to happen, getting a hearty dose of natural light in the mornings can at least help get your internal clock back on track.

Jet lag and other sleep problems are actually considered circadian rhythm disorders. Speaking of jet lag: Disruption to your normal sleep patterns -- whether it’s from mismatched internal and external cues, as in social jet lag, or a “malfunction” in your personal circadian clock, as in narcolepsy -- can lead to both insomnia and excessive sleepiness, according to the Cleveland Clinic. These types of sleep problems are dubbed circadian rhythm disorders, a category that also includes Delayed Sleep Phase Disorder, or extreme night owl tendencies, Advanced Sleep Phase Disorder, typically seen in older people who go to sleep in the early evenings and wake up in the very early mornings, and shift work disorder, which affects people who either work at night or regularly change their work times in a way that affects their sleep.

Some of our genes operate on internal “clocks” and messing with your sleep upsets almost all of them. These genes control everything from body temperature to blood sugar and possibly even mood. But after putting participants in a small study on a 28-hour day until their sleep schedules were 12 hours off from normal, researchers found nearly all of these genes were out of whack. "Over 97 percent of rhythmic genes become out of sync with mistimed sleep and this really explains why we feel so bad during jet lag, or if we have to work irregular shifts," study researcher Simon Archer, Ph.D., said in a statement.

Some of those genes affect the immune system. You can probably recall a time when you skimped on sleep one too many nights in a row and ended up with a nasty cold: Lack of sleep can definitely hurt your immune response. But recent research in animals has started to explore why that is, and findings suggest that certain genes responsible for fighting off bacteria and viruses are also controlled by the circadian clock.

"If we have a better understanding of how specific immune markers are affected or changed by disruptions in our circadian rhythm, then we may be better able to advise the public on how to potentially ward off sickness, especially when they might be more vulnerable to a cold, flu or virus," Rebecca Scott, a sleep specialist at the New York Sleep Institute, previously told The Huffington Post.

A wonky circadian clock could affect fertility. Women who are hoping to conceive or who are already pregnant should take extra precautions in keeping the bedroom free of artificial light. Turns out, every time you confuse your circadian rhythm, you might be confusing your "biological clock," too. In a 2014 review, researchers reported that the production of melatonin, triggered naturally by on-schedule circadian rhythms and stunted by artificial light late at night, protects a woman’s eggs from stress, because of its antioxidant powers.

Sleep problems in people with depression may be due to faulty circadian clocks. A 2013 study compared brain samples from mentally healthy organ donors with samples from donors who were clinically depressed at the time of their deaths. The gene activity in the brains of the depressed people was shown to deviate from the healthy 24-hour cycle of a normal circadian rhythm. "They seem to have the sleep cycle both shifted and disrupted," study researcher Jun Li, a professor of human genetics at the University of Michigan, told LiveScience. "They seem to be sleeping at the wrong time of the day, and the quality of their sleep is also different from healthy sleep.”

Even fruits and veggies have circadian clocks. Your favorite produce isn’t necessarily “dead” once it’s been harvested: Fruits and vegetables have their very own internal clocks that keep on ticking up and down grocery store aisles, according to a 2013 study. "They respond to their environment for days, and we found we could use light to coax them to make more cancer-fighting antioxidants at certain times of day,” Janet Braam, the study's lead researcher and chair of the department of biochemistry and cell biology at Rice University, said in a statement.